1. Field of the Invention
This invention is related to an improvement in the structure of a capped lock nut and in particular to one which can be easily manufactured.
2. Description of the Prior Art
The conventional capped lock nut generally includes a nut body formed with an upwardly extending flange on which is welded a cap for preventing dust or like to enter into the nut body. However, such a capped lock nut is easily loosened when subject to vibration. Hence, a nylon packing has been proposed to be secured on the top of the nut body in such a way that the upper portion of the nylon packing extends upwardly out of the nut body and a cap is riveted or otherwise secured to the top of the nut body. Nevertheless, the cap will be easily separated from the nut body when the lock nut is engaged with a long screw thereby producing sharp edges and therefore often causing injuries to the operator. Hence, it must be very careful to engage such a capped lock nut with a long screw thus making it difficult to use and increasing the cost. The reason why the cap is riveted but not welded to the nut body is that the nylon packing will be deformed or even melted if the cap is welded to the nut body. In addition, it is time-consuming to fasten the cap on the nut body by rivets thereby lowering the production rate and therefore increasing the cost.
Therefore, it is an object of the present invention to provide an improvement in the structure of a capped lock nut which can obviate and mitigate the above-mentioned drawbacks.